&lt;title&gt;Investigation of metal contamination by photocurrent measurements: validation and application to ion implantation processes&lt;/title&gt;

Polignano, M. L.; Bresolin, C.; Cazzaniga, F.; Sabbadini, A.; Queirolo, G.

doi:10.1117/12.221187

Cited by 16 publications

(9 citation statements)

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“…Contamination by sputtering.-Ion implantation is known to be responsible for metal contamination, specifically for high dose implantations of heavy ions. It was shown 43 that an important contribution to contamination from implantation processes is due to material sputtered from the loading disk and then captured by the implantation beam. The contamination carried by this mechanism comes from the side exposed to the ion beam and increases proportionally with increasing implantation dose.…”

Section: Resultsmentioning

confidence: 99%

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Review—Characterization of Metal-Contamination Effects in Silicon

Polignano

Codegoni

Galbiati

et al. 2015

ECS J. Solid State Sci. Technol.

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Various measurement techniques are compared and the most suitable methods for contamination detection are identified. The results of this study show that it is not possible to define a unique recipe that can be applied in all cases. Concerning metal contaminants, the stratigraphic in-depth distribution and hence the diffusivity of contaminants determines the most effective approach. Iron and palladium are chosen as the examples of fast diffusers, molybdenum and tungsten as slow diffusers. Fast diffusers like iron and palladium diffuse through several hundred microns during an ordinary thermal treatment. Minority carrier lifetime measurements are probably the best choice to detect these contaminants. Molybdenum and tungsten do not diffuse deep enough to be efficiently revealed by recombination lifetime measurements, but are easily revealed in the silicon volume by DLTS. Because of their low diffusivity, a very small amount of these elements per unit surface may result in a significant concentration in the near-surface region where devices are built. Ion implantation is confirmed to be an important source of metal contamination. It is shown that ion implantation can be responsible both for iron contamination and for contamination by slow diffusers, such as molybdenum and tungsten. A procedure for monitoring molybdenum and tungsten contamination in ion implantation processes by DLTS is defined and calibrated. Finally, the efficiency of some gettering techniques in reducing iron, molybdenum and tungsten contamination is discussed. Gettering is found to be active at relatively high contaminant concentrations, but low contamination levels are not gettered under our experimental conditions. Carbon implantation showed partial efficiency in gettering molybdenum and tungsten, whereas gettering did not take place after silicon implantation.

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Section: Resultsmentioning

confidence: 99%

“…This mechanism is usually responsible for near-surface contamination, because contaminant atoms reach the wafer with very low energy. 43,44 Therefore, the tungsten dose estimated from the data in Fig. 16 can be compared with TXRF measurements of surface contamination after implantation.…”

Section: Resultsmentioning

confidence: 99%

Review—Characterization of Metal-Contamination Effects in Silicon

Polignano

Codegoni

Galbiati

et al. 2015

ECS J. Solid State Sci. Technol.

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“…For example, to fabricate of different thicknesses and dopant densities with p+ layers PiN diodes by CVD or ion implantation, different fabrication parameters are required, and these parameters give rise to a difference in the amount of heavy-metal contamination in the i-layer. 21,22) As described, in Sect. 1, recombination lifetime depends on the amount of impurities in a semiconductor.…”

Section: Verification Experiments Of New Equations To Eliminate the E...mentioning

confidence: 99%

New equations to calculate carrier recombination lifetime of silicon epitaxial layer, based on open circuit voltage decay method

Sasaki,

Mitsugi,

Samata

et al. 2023

Jpn. J. Appl. Phys.

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New equations for recombination lifetime calculation based on the open circuit voltage decay (OCVD) method were proposed. The new equations can yield accurate recombination lifetime values of the i-layer of PiN diodes in which a silicon epitaxial layer is employed, by eliminating the effects of carrier diffusion into p+ and n+ layers from the i-layer of PiN diodes, carrier injection into the i-layers from the depletion layer of PiN diodes, and surface recombination on the side wall of PiN diodes. To verify the effectiveness of the new equations, OCVD measurements were performed by employing technology computer-aided design (TCAD) simulation and actual PiN diodes. Although the calculated values implied the effect of epitaxial layer thickness, they were consistent with the results obtained under assumed lifetime conditions for TCAD simulation, the theory of recombination lifetime, and results in other reports.

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“…Contamination by sputtering. It was previously shown (33) that contamination by sputtering is very effective in arsenic implantations, and that this contamination mechanism can be suppressed by a suitable design of the wafer holder (34). However, contamination by sputtering is still possible if the implantation equipment has been previously contaminated, for instance by implantation of wafers with an exposed metal layer.…”

Section: Contamination In Ion Implantationmentioning

confidence: 99%

“…In this experiment, contamination is mainly due to sputtering from parts close to the wafer during implantation. This mechanism is usually responsible for near-surface contamination, because contaminant atoms reach the wafer with very low energy (33,34). Therefore, the tungsten dose estimated from the data in Figure 4(b) can be compared with TXRF measurements of surface contamination after implantation.…”

Section: Contamination In Ion Implantationmentioning

confidence: 99%

(Invited) Metallic Impurity Control in Silicon Processing

Polignano¹,

Borionetti²

2022

ECS Trans.

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The performances of a few techniques for the analysis of metal contamination in silicon are reviewed. The chemical dissolution of a polysilicon gettering layer associated to ICP-MS (Inductively Coupled Plasma - Mass Spectroscopy) analysis, TXRF (Total Reflection X-Ray Fliuorescence) Recombination lifetime measurement techniques, DLTS (Deep Level Transient Spectroscopy) and micro-photoluminescence analyses are compared. A few case studies are discussed to test the ability of these techniques in detecting contaminants with different properties as silicon impurities. The results reported in this paper show that it is not possible to define a unique recipe that can be applied in all cases. Different approaches are required depending, on one hand, on the contaminant diffusivity and solubility, and, on the other hand, on the process step to be monitored. Finally, we show that the device itself can be a sensitive monitor of metal contamination.

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<title>Investigation of metal contamination by photocurrent measurements: validation and application to ion implantation processes</title>

Cited by 16 publications

References 0 publications

Review—Characterization of Metal-Contamination Effects in Silicon

Review—Characterization of Metal-Contamination Effects in Silicon

New equations to calculate carrier recombination lifetime of silicon epitaxial layer, based on open circuit voltage decay method

(Invited) Metallic Impurity Control in Silicon Processing

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